The solvent vent mode is how the Multi Mode Inlet is able to do Large Volume Injection (LVI). In solvent vent mode, the inlet is kept at a low initial temperature during sample application. Pneumatically, the inlet is in split mode with a low inlet pressure. The flow of gas through the inlet liner and out to vent removes the evaporating solvent. The sample is injected so that the incoming liquid is deposited on the liner wall and the solvent evaporates at a similar rate. Once the entire sample has been injected, the inlet switches to a splitless mode for analyte transfer. The inlet is then heated to vaporize the concentrated sample and any remaining solvent and they are transferred to the column. After a sufficient period to ensure the sample transfer, the inlet is then switched to a purge mode to allow any remaining material in the inlet liner to be removed to waste. During the sample injection and solvent venting period, the GC oven has been held at an appropriate temperature to allow the solvent to refocus the analytes on the column. When this refocusing is complete, the oven is then programmed to perform the separation.
Please refer to the following document for more information about Solvent Elimination Calculator (page 12) which will calculate the solvent vent time along with other parameters.
Agilent Multimode Inlet